1. Technical Field
An automated clamp system for a fluid mixer is disclosed with an effective means for accurately detecting when the upper clamp plate engages the top of a container placed in the mixer and for communicating the engagement of the upper clamp plate with the container to the controller for use in carrying out a clamping algorithm.
2. Description of the Related Art
Many types of fluids need to be mixed or blended into homogenous mixtures in the same containers in which they are sold to a consumer. One example of such in-container mixing results from colorants or pigments being added to base paints at a retail paint store or paint department of a home improvement store. The mixers or mixing machines may operate by vibration, roto-vibration, gyroscopic motion or rotational motion. The forces exerted on the containers during the mixing process are violent.
To ensure that the container or containers stay in position during the violent mixing operation, various clamping mechanisms have been employed. Until recently, the amount of clamping force imposed on a conventional metal cylindrical container (e.g., 1 gal.) or plastic cylindrical container (e.g., 5 gal.) was not crucial as the containers were extremely rugged, and therefore it is difficult to damage a conventional container by over-clamping.
However, paint has become available in rectangular and cubical plastic containers which are not as robust as the conventional cylindrical containers. Further, there is a need to blend or custom mix colors of paint in the new rectangular containers. One rectangular paint container has a handle molded into one corner for the painter's convenience in pouring paint from the container. Such a rectangular paint container has a rectangular or square footprint or cross section. Another new type of container includes rectangular trays or trough-like buckets sized to receive a paint roller. Some of the rectangular trays or troughs may be pre-equipped with a screen or insert for engaging the roller. Smaller plastic cylindrical containers are also being used instead of the traditional metal cylindrical containers.
The new types of containers are fabricated from plastic and are less robust than the conventional counterparts. Hence, an automatic clamping mechanism of a prior mixing machine is capable of crushing most, if not all, of the new types of containers. To avoid the problem of containers being crushed by the mixing machines and the spillage of paint, new and improved clamping mechanisms and automated clamping mechanisms are needed. Further, such clamping mechanisms must be versatile and capable of use on the various types of containers in the marketplace, both old and new.
In that connection, one key element of any automated clamping system is determining when the upper clamping plate engages the top or lid of the container or containers that has been loaded into the mixer. The initial engagement of the upper plate with the container or containers loaded into the machine is a starting point for many sophisticated clamping algorithms and needs to be communicated accurately to the control circuit or controller. If this information is not accurately detected and communicated, the timing of the clamping algorithm may be off resulting in damage to the container or containers by the over application or under application of clamping force.